Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Hazard Symbols: Chemicals in the lab are labeled with symbols to communicate risks. Common symbols include Corrosive (can cause chemical burns to skin and eyes) and Irritant (causes redness or blistering).
Concentration: The danger of a substance depends on its concentration. Concentrated acids like are far more dangerous than dilute solutions.
Personal Protective Equipment (PPE): Always wear safety goggles to protect eyes from splashes of acids like or alkalis like . Lab coats protect clothing and skin.
Safe Handling: Never taste chemicals. When smelling a substance, use the 'wafting' technique rather than sniffing directly to avoid inhaling toxic vapors.
Neutralization Safety: Mixing an acid and an alkali can be an exothermic reaction (releases heat). This should be done slowly to avoid splashing.
Emergency Procedures: If an acid or alkali touches the skin, it must be washed immediately with plenty of running to dilute and remove the chemical.
📐Formulae
💡Examples
Problem 1:
A bottle of concentrated nitric acid () has a symbol showing a hand and a metal bar being eaten away. What does this symbol represent and what precaution should be taken?
Solution:
The symbol represents 'Corrosive'.
Explanation:
Corrosive substances can attack and destroy living tissue and materials. Precautions include wearing chemical-resistant gloves, safety goggles, and ensuring the is handled over a spill tray.
Problem 2:
During an experiment, a student needs to dilute a concentrated sample of . What is the safe way to mix the acid and water?
Solution:
Always add the acid to the , never add water to concentrated acid.
Explanation:
Adding water to concentrated sulfuric acid can cause a violent exothermic reaction, resulting in the mixture boiling and splashing acid out of the container.